Virtual fonts
Virtual fonts provide a convenient and flexible way to specify a
mapping from TEX's notion of a font character to the
capabilities of a particular output device (e.g., screen or printer).
In particular, virtual fonts make it easy to use PostScript fonts with TEX.
The definitive document on virtual fonts is Donald Knuth's article
in TUGboat vol. 11 no. 1. A text version called ``Knuth on VFs''
can be seen in 's Help menu.
and dvips process virtual fonts automatically,
so most people never need to worry about whether or not a DVI file
uses such fonts. To decide if font foo is virtual,
and dvips look for a file called foo.vf
in the current folder, then in the list of folders specified by
vf_folders.